Cancer is a serious health problem as well as a scientific challenge. A lot has been learned about the process of transformation of a normal cell into a tumor cell by studying genes and proteins that regulate this process either in cis or in trans. However, whether these molecular mechanisms succeed in fulfilling their potential to give a clinically evident disease depends in great measure on the host response to those molecular changes. The work of my laboratory aims to provide evidence in animal models as well as in cancer patients that immune system can control cancer growth and that this important function can be improved through vaccination with well-defined tumor antigens.